U.S. patent number 4,468,371 [Application Number 06/399,920] was granted by the patent office on 1984-08-28 for immunoassay test slide.
This patent grant is currently assigned to Daryl Laboratories, Inc.. Invention is credited to Anthony B. Chen, Richard A. Harte, Nancy K. Kaufman.
United States Patent |
4,468,371 |
Chen , et al. |
August 28, 1984 |
Immunoassay test slide
Abstract
A test slide for the performance of a series of immunoassay
tests having: a substantially elongated and thin body of solid
material; a plurality of individual test wells formed in said body;
alignment means formed in said body in association with each of
said wells; and movement facilitating means formed in said body;
said slide being suitable for insertion into an automated testing
device, said slide moving by said movement facilitating means, and
said wells being aligned for detection by said alignment means.
Inventors: |
Chen; Anthony B. (Hayward,
CA), Harte; Richard A. (Redwood City, CA), Kaufman; Nancy
K. (Belmont, CA) |
Assignee: |
Daryl Laboratories, Inc. (Santa
Clara, CA)
|
Family
ID: |
23581491 |
Appl.
No.: |
06/399,920 |
Filed: |
July 19, 1982 |
Current U.S.
Class: |
435/288.4;
422/65; 435/287.2; 436/809 |
Current CPC
Class: |
G01N
33/5304 (20130101); Y10S 436/809 (20130101) |
Current International
Class: |
G01N
33/53 (20060101); G01N 033/54 (); G01N 035/00 ();
G01N 035/02 () |
Field of
Search: |
;435/293,300 ;422/102,65
;436/809 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Marantz; Sidney
Attorney, Agent or Firm: Kolisch, Hartwell, Dickinson &
Anderson
Claims
What is claimed is:
1. A test slide for the performance of a series of immunoassay
tests comprising
a substantially elongated and thin body of solid material;
a plurality of individual test wells formed in said body,
alignment means formed in said body in association with each of
said wells, and
movement facilitating means formed in said body,
said slide being suitable for insertion into an automated testing
device, said slide moving by said movement facilitating means, and
said wells being aligned for detection by said alignment means.
2. The test slide described in claim 1 wherein a horizontal
cross-section of each of said test wells is substantially circular
in shape.
3. The test slide of claims 1 or 2 wherein the acute angle formed
between the plane of said bottom surface of each test well and its
associated diverging sidewall is approximately 68.degree..
4. The test slide of claim 3 wherein each test well has a depth of
approximately 0.080 inches, said bottom surface has a diameter of
approximately 0.188 inches and the opening of each test well has a
diameter of approximately 0.25 inches.
5. The test slide as described in claim 4 wherein an
immunosubstrate layer is formed in the bottom of each said test
well to aid in the performance of immunoassay testing.
6. The test well of claim 5 wherein said immunosubstrate layer has
a thickness of approximately 0.004 inches.
7. A test slide for the performance of a series of immunoassay
tests employing an automatic testing device comprising:
a substantially elongated and thin body of solid material;
a rack formed along one elongated edge of said body for engagement
with an automatic testing device;
a plurality of test wells substantially evenly spaced in a linear
manner along the length of said body; and
a plurality of notches formed in said body, each notch being
positioned in alignment with a different one of said test wells,
thereby to align the wells in the automatic testing device.
8. A test slide for the performance of a series of immunoassay
tests comprising:
a substantially elongated and thin body of solid material;
a plurality of test wells formed in said body, each of said test
wells having a substantially flat bottom with an immunosubstrate
layer having a thickness of approximately 0.004 inches deposited
thereon;
diverging sidewalls joined to and extending away from said bottom
surface;
a rack formed along one elongated edge of said body for engagement
with an automated testing device; and
a plurality of notches formed in said body, each notch being
positioned in alignment with one of said test wells, thereby to
align said wells within the testing device.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates generally to test slides for
performing immunoassays and more particularly to an immunoassay
test slide suitable for use in immunoassay testing which contains a
series of test wells each having an immunosubstrate layer formed
therein.
2. Description of the Prior Art
Immunoassay test slides having a series of test wells formed
therein have been known in the industry for many years. Such test
slides contain wells of varying shapes and sizes and are suitable
for differing test procedures. Thus the prior art contains a test
well shape consisting of a rounded bottom with diverging sidewalls,
a test well shape consisting of a flat bottom and vertical
sidewalls, and a test well shape consisting of a rounded dish shape
having curved sidewalls.
In recent years, it has been found that immunoassay test results
may be enhanced through the utilization of an immunosubstrate. The
immunosubstrate serves to provide substantially increased numbers
of binding sites for immunoreagents utilized in the test
procedures. The enhanced binding capacity has created greater
sensitivity to immunoassay tests utilizing immunosubstrates.
It therefore appeared innovative to place an immunosubstrate layer
within individual test wells of the prior art test slides in order
to enhance test results obtained therefrom. However, when tests
were performed by the instant inventors utilizing an
immunosubstrate in the various prior art test wells, inconsistent
and inaccurate results were often obtained. It appeared that
immunoreagents within the immunosubstrate layer gravitated to the
sides of test wells having vertical sides. Test wells having
rounded bottoms performed poorly and inconsistently for no obvious
reason. It is the inventors hypothesis that the manner in which the
immunosubstrate dries after wetting and the possible gravitation of
immunoreagents during the drying process to particular areas of the
immunosubstrate layer, such as to a ring towards the edge of the
vertically sided well, contribute to the poor and unreliable
results.
SUMMARY OF THE PRESENT INVENTION
It is therefore a primary objective of the present invention to
provide an optimally shaped test well for performing
immunoassays.
It is another objective of the present invention to provide an
immunoassay test slide having a series of optimally shaped test
wells formed therein for the rapid and accurate performance of
immunoassay tests.
It is a further object of the present invention to provide an
immunoassay test slide which is formed for automated testing within
a immunoassay testing device.
The optimally shaped test well of the present invention has a flat
bottom and diverging side walls. The test well has sufficient depth
to contain an immunosubstrate layer and liquid immunoreagents which
will be placed in the test well to react within the immunosubstrate
layer.
The immunoassay test slide of the present invention contains a
series of said optimally shaped test wells. Further embelishments
of the test slide which aid in its utilization in an automated
testing device include an edge formed as a rack for interaction
with a pinion gear within the testing device and notches formed in
an edge thereof for the accurate alignment of individual test wells
with testing components within the testing device.
An advantage of the present invention is that accurate, sensitive
and reproducible results are now obtainable utilizing test wells of
the particular shape described herein along with suitable
immunosubstrate materials.
Another advantage of the test slide of the present invention is
that it may be utilized in an automated testing device such that
accurate results for a series of tests may be obtained rapidly and
inexpensively.
These and other objects and advantages of the present invention
will no doubt become apparent to those of ordinary skill in the art
after having read the following detailed description of the
preferred embodiments which are illustrated in the several figures
of the drawing.
IN THE DRAWING
FIG. 1 is a top plan view of the immunoassay test slide of the
present invention;
FIG. 2 is a left side elevational view of the immunoassay test
slide shown in FIG. 1;
FIG. 3 is a right side elevational view of the immunoassay test
slide shown in FIG. 1;
FIG. 4 is a bottom plan view of the immunoassay test slide of the
instant invention;
FIG. 5 is a cross-sectional view of the immunoassay test slide
shown in FIG. 1, taken along lines 5--5 of FIG. 1 and depicts
details of the test well formed therein;
FIG. 6 is a rear elevational view of the immunoassay test slide
shown in FIG. 1; and
FIG. 7 is a front elevational view of the immunoassay test slide
shown in FIG. 1.
DESCRIPTION OF THE PREFERRED EMBODIMENT
As depicted in FIGS. 1, 2 and 3, the preferred embodiment of the
immunoassay test slide of the present invention 10 is basically a
long thin strip of material having a series of test wells 12 formed
therein. A suitable material is a polystyrene plastic however,
other materials may be substituted therefore. When viewed from
above, as in FIG. 1, it is seen that the test wells 12 are evenly
spaced in a linear manner throughout the length of the slide 10.
The spacing of the wells 12 from center line to center line is
approximately 0.354 inches, such that standard industry microtiter
equipment may be utilized therewith.
The preferred embodiment of the immunoassay test slide 10 is formed
for utilization in an automated testing system, not shown. The
basic elements of the slide 10 which permit its movement within the
automated testing system are a rack 14 which is formed along one of
the elongated edges 16 of the slide 10. The depiction of the rack
14 in FIGS. 4, 5 and 6, will aid in the understanding of this
feature. The rack 14 is formed for engagement with a pinion gear
within an automated testing device to permit the controlled
movement of the slide 10 within the automated testing device. The
invention is not to be limited to only this type of rack 14 for the
movement of the slide.
To accomplish the accurate alignment of individual test wells 12
within an automated testing device a series of notches 18 are
formed in the other elongated edge 20 of the slide 10. An enhanced
understanding of the notches 18 in edge 20 is to be gained from
FIGS. 4, 5 and 7. Each of the notches 18 is formed in a prearranged
accurate alignment with the wells 12 such that when the slide 10 is
inserted within an automated testing device a suitable sensing
device can detect the presence of a notch 18 along edge 20 to
accurately align each individual test well 12 with a test detection
system within the automated testing device. It is crucial to the
creation of accurate and reproducible results from an automated
test system utilizing the slide 10 that each test well be
accurately and identically aligned relative to the test detection
system within the automated testing device. The instant invention
is not to be limited to the type of alignment system described
herein, as equivalent systems may be easily substituted
therefor.
A detailed depiction of the shape of each test well 12 of the slide
10 is presented in FIG. 5. As depicted therein, each test well is
formed with a flat bottom 30 and has diverging sidewalls 32. The
acute angle between the plane of the base 30 and the sidewall 32 in
the preferred embodiment is formed to be approximately 68.degree..
In the preferred embodiment, the diameter of the upper opening of
each test well is approximately 0.250 inches, the diameter of the
flat bottom 30 of each test well is approximately 0.188 inches and
the depth of each test well is approximately 0.080 inches.
An immunosubstrate layer 34 is shown in the test well 12 of FIG. 5.
A typical immunosubstrate layer 34 would have a thickness of
approximately 0.004 inches and would exhibit a slight creeping 36
up the diverging sides 32 of the test well 12. The immunosubstrate
layer 34 is utilized to provide a substantially increased number of
binding sites for immunoreagents utilized in performing tests
within the test well 12. The utilization of an immunosubstrate
greatly increases the sensitivity and accuracy of immunoassays.
The above-described test well of the preferred embodiment, having a
flat bottom and diverging sidewalls, when used with an
immunosubstrate, has demonstrated in testing that it provides test
results which are more consistent and accurate than test results
obtained using preexisting test wells of differing shapes and the
identical immunosubstrate.
More specifically, one type of prior art test well, possessing a
rounded bottom together with diverging sidewalls was examined. When
an immunosubstrate, consisting of latex polymer bead emulsion in
water, was placed in the bottom of this test well and testing was
conducted, the results were inconsistent from test well to test
well and generally inaccurate. The inventors are unsure of the
precise reasons for the inconsistency and inaccuracy, but believe
that the rounded bottom of the test well created a deep pocket of
immunosubstrate material which dried more slowly than the outer
regions. It is believed that the uneven drying resulted in uneven
concentrations of immunoreagents within the immunosubstrate and
produced the inconsistent and inaccurate results. Additionally, it
is believed that the rounded geometry of the well inhibits
effective washing of unbound reagents from the immunosubstrate
prior to the testing thereof. This effect also would tend to create
poor results.
Further testing was conducted utilizing the prior art test wells
which have a flat bottom and vertical sidewalls; the identical
immunosubstrate was utilized to form a layer therein. Again,
inconsistent and inaccurate results were obtained, as compared with
those of the preferred embodiment. The inventors are unsure of the
cause of the poor results, but it appeared that substantial
creeping of the immunosubstrate up the walls of the test well was
occurring. It is hypothesized that the vertical test walls create a
shielding or shadowing effect such that the optical instruments
utilized to perform the immunoassay testing could not accurately
detect immunoreagents which had crept up the side walls.
Additionally, the vertical sidewalls appeared to inhibit effective
washing of the outer edges of the immunosubstrate. This would tend
to permit unbound reagents to remain in the immunosubstrate and
lead to inconsistent and inaccurate results. Again, the inventors
were uncertain of the cause of the poor results and confirmed that
the test well shape of the preferred embodiment is substantially
superior.
A third prior art test well in the shape of a fully rounded
depression was also examined. Test results utilizing this prior art
shape with the immunosubstrate also proved inconsistent and
inaccurate. The inventors believe the source thereof to be the
rounded bottom which creates uneven drying and difficulty of
washing of the immunosubstrate in the bottom of the test well, as
was described hereinabove.
The instant invention achieves consistent and accurate immunoassay
testing results through the utilization of a specially shaped test
well 12 having a flat bottom and diverging sidewalls. The placement
of a series of such test wells 12 in the instant test slide along
with the utilization of the alignment notches 18 and rack 14 permit
the slide 10 to be utilized in an automated immunoassay testing
system to produce accurate results rapidly and inexpensively.
Whereas the preferred embodiment of the present invention has been
described above, it is contemplated that other alterations and
modifications may become apparent to those skilled in the art after
having read the above disclosure. It is therfore intended that the
appended claims be interpreted as covering all such alterations and
modifications as fall within the true spirit and scope of the
invention.
* * * * *